As a national Republican wave crested on Election Day, there were several campaigns in both parties that stood out as outstanding operations.

The GOP expanded its House majority and obtained control of the Senate. As a result, more Republican campaigns emerged deserving of the spotlight. But there were also several Democratic operations worthy of recognition.

Updated Nov. 5, 7:23 a.m. | Republicans swept the Senate races Tuesday night, and come January, they will control the chamber for the first time in eight years.

Democratic incumbents fell right and left, even in seats that they had originally been favored to win. President Barack Obama's poor approval rating — 42 percent in the last nationwide Gallup poll — dragged down candidates across the country in the face of a Republican wave.

Roll Call's final ranking of the most vulnerable senators doesn't vary much from previous versions — the result of an unfavorable national climate for Democrats that has failed to improve.

On the eve of the midterm elections, Senate Democrats are staring down a hole dug by President Barack Obama’s disapproval ratings and an unforgiving map packed with red states. Retirements by a quartet of senators in Republican-leaning or swing states didn’t help, but the seats of at least four incumbents seeking re-election aren’t on much stronger ground.

"What Joni Ernst would mean, coming to the United States Senate, is that Mitch McConnell would be the leader of the Senate, someone who agrees with her on virtually everything. Think what that would mean to our country," Reid told progressives Saturday, when asked about Ernst's chances in the open-seat race in Iowa.

When the myriad Republican presidential contenders start campaigning for 2016, their journeys might not look much different from this cycle.

From Iowa to New Hampshire, every Republican who is even remotely considering a 2016 bid hit the trail this year to help Senate contenders. What's more, several competitive Senate races are this year conveniently in states that play host to early nominating contests in 2016.

Every week after President Barack Obama delivers his weekly address, the Republicans get a chance to respond. Because they don't, of course, have a singular figure who would naturally address the nation each week, the speakers vary. So far in 2014, 11 Republican candidates — four House hopefuls and seven vying for Senate seats — have had the honor to take to YouTube and spread their party's message.

In the fall of an election year, the GOP weekly address is an opportunity for Republicans to showcase some of their hopefuls on the ballot to a broader audience than the candidates can normally reach themselves — because not everyone pays attention to every Senate race, or to New York congressional campaigns.